Study on phenolic resin foam modified by montmorillonite and carbon fibers

Abstract

In this article, phenolic resin was modified by montmorillonite(MMT) carbon fiber and other addition agents. This composite phenolic foam was characterized by XRD, SEM, and TEM the mechanical properties of this composite foam were measured as well. The results show that exfoliated phenolic resin/montmorillonite nanocomposites are obtained from acidulated montmorillonite (H-MMT) and phenolic resin by in-suit polymerization, the thickness of MMT layers is about 20-40nm, and the affinity between the MMT and phenolic resin is very good. During the forming of phenolic foams, because of the inflation of bubbles and the streching of bubble walls, MMT layers possess a certain orientation in this composite foam, forming a structure in which bubbles are wrapped around by MMT layers. So the degree of pulverization is decreased, and the compressive strength of this foam is increased by 35%-40%. Besides, MMT layers dispersed in this foam contribute greatly to its antiflaming and better properties. However, when the content of H-MMT is above 7%, MMT agglomeration appears. On the other hand, when carbon fibers are added to phenolic resin as a crosslink, they can prevent cracks from developing. Due to the excellent mechanical property and thermostability of carbon fibers, the flexural strength is increased by 58%, and the carbon yield ratio of composite foam is improved by no less than 8% when it is heated to over 500°C.